Image Sensor Cleaning for Reliable Sheet Skew Detection
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Solution Overview
Problem
Existing image forming apparatuses face issues with false detection of sheet skew and lateral deviation due to foreign substances on the image sensor's reading surface, leading to inaccurate sheet alignment and printing defects.
Innovation Solution
The apparatus incorporates a control device that senses foreign substances on the image sensor's reading surface using output signals, and employs a cleanup device, either a rotating cleanup roller or a movable cleanup body, to remove these substances, ensuring accurate sheet alignment by correcting skew and lateral deviation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the image sensor continuously monitors the sheet for skew and lateral deviation, then the sheet alignment precision is improved, but the risk of false detection due to foreign substances on the reading surface increases
Solution Approach 1:
The system performs preliminary cleaning of the image sensor reading surface before sheet detection, and continuously monitors for foreign substances during operation. This preventive measure eliminates foreign substances before they can cause false detection, while maintaining continuous sheet alignment monitoring capability
Solution Approach 2:
A dedicated cleanup device is introduced as an intermediary component between the image sensor and the sheet. This cleanup device includes a cleanup roller or cleanup body that physically removes foreign substances from the reading surface, acting as a mediator to protect the sensor from contamination while allowing continuous operation
2Reliability
If a cleanup device is added to clean the image sensor surface, then the false detection rate is reduced, but the device complexity increases
Solution Approach 1:
The cleanup device is integrated into the existing sheet conveyance path and positioned to work in conjunction with the image sensor without requiring separate independent systems. The cleanup roller or body is arranged to clean the sensor surface as part of the normal operational cycle, merging the cleaning function with the existing detection system
Solution Approach 2:
The image sensor system performs self-maintenance through the integrated cleanup device that automatically removes foreign substances from the reading surface during operation. The system monitors its own sensor condition and triggers cleaning when foreign substances are detected, enabling self-service maintenance without external intervention
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution effectively prevents false sensing of sheet deviation, maintaining precise sheet alignment and improving printing quality by regularly cleaning the image sensor's surface.
Implementation Method 1
The image sensor reads the sheet on an upstream side of the transfer position in a sheet conveying direction... the control device senses a foreign substance on a reading surface of the image sensor as well as calculate a lateral deviation amount and/or a skew amount of the sheet based on the output signal of the image sensor
Implementation Method 2
the cleanup device may include a cleanup roller which rotates about a rotation shaft arranged along the main scanning direction. In this case, the cleanup device causes the cleanup roller to rotate, to clean the reading surface of the image sensor
Implementation Method 3
the cleanup device may include a cleanup body movable in the main scanning direction. In this case, the cleanup device causes the cleanup body to reciprocate, to clean the reading surface of the image sensor
Data Source
AI summary
An image forming apparatus is capable of correcting a lateral deviation and/or a skew of a sheet. A pair of conveying rollers convey the sheet to a transfer position of an image. An image sensor reads the sheet on an upstream side of the transfer position in a sheet conveying direction. A control device senses a foreign substance on a reading surface of the image sensor as well as calculate a lateral deviation amount and/or a skew amount of the sheet based on an output signal of the image sensor.